H34D-05:
Groundwater Estimation Using Remote Sensing Data on a Catchment Scale in New Zealand
Abstract:
Long-term time series of satellite evapotranspiration (ET) were trialled for their additional value in aquifer characterisation on the catchment scale in New Zealand. In a simple chain-of-events approach yearly natural groundwater recharge was calculated with a 1x1km resolution. The chain consisted of (1) rainfall; (2) runoff due to slope; (3) actual ET; (4) soil permeability and water holding capacity; and (5) hydraulic conductivity of the deeper geology. As ET is a large part of the water balance (in New Zealand on average appr. 50% of rainfall), high resolution and high quality ET data is important for estimating groundwater recharge.Most global satellite data
We then used national data to estimate 1x1km natural groundwater recharge: the corrected MOD16 PET and AET, in-situ based precipitation models; soil maps; geology maps; and (satellite-based) elevation. Validation with lysimeters and existing sub-catchment model output data looks promising, and further improvement with satellite soil moisture to estimate monthly recharge is underway.
This work was done in the SMART Aquifer Characterisation (SAC) programme, a six-year research project funded by the New Zealand Ministry of Business, Innovation en Employment.
Figure: Mean annual 1x1km PET (2000-2012) from MODIS MOD16 data, corrected for ground stations.